The present invention relates generally to methods and apparatus for treating industrial waste matter, and more specifically relates to methods and apparatus for removing contaminants from such water, having particular applicability to treatment of waste water from vehicle washing, laundries and similar operations.
The recovery of waste water from industrial operations is presenting an increasing problem relative to environmental and governmental concerns. The impact upon the environment by water used in industrial operations, including vehicle washing operations, is being recognized as an increasing problem. Accordingly, governmental regulations, at both the local and federal level, are being put into place to require the clean up of industrial water prior to release to the environment or into a public sewer system.
Several significant problems are presented in the clean up of industrial waters. These are exemplified by the problems with the cleaning of waters used in vehicle washing operations. Accordingly, the present invention will be discussed in relation to such systems. Water used for vehicle washing typically contains significant amounts of suspended solids; and will also contain significant amounts of undesirable dissolved minerals. Wash waste water will also typically include significant amounts of organic materials, including oils and other hydrocarbons and bacteria. Further, detergents and other chemicals used in the wash operation present further difficulties to cleaning and reclaiming the water.
A number of water recapturing and reclaiming systems have been proposed. Such systems utilize conventional techniques to remove certain contaminants from the water. Conventionally proposed systems suffer from at least one of the drawbacks that (a) the systems are complex, requiring either highly sophisticated controls or requiring highly skilled operators; or (b) the systems remove certain impurities or contaminants at the expense of leaving others.
For example, it is well-known that suspended solids can be removed from water by allowing the solids to settle out in a still pool. In some systems, this is performed through use of a flocculating tank. Such systems allow the solids to settle out in a still pool. A still pool, however, is an optimal breeding ground for bacteria, which typically give off a strong and unpleasant odor. Additionally, such systems typically require a substantial volume of space.
Alternatively, solids can be removed with cartridge or bag filtration. Each of these systems is advantageous, depending upon the volume of solids in the influent. Cartridge or bag filters will have to be replaced often if a large number of solids of the filtered size are present in the water. Accordingly, cartridge or bag filters are typically not appropriate where large volumes of solids will be recovered. Additionally, where hydrocarbons are present in the water, as is typically the case in vehicle washing operations, cartridge or bag filters can easily become plugged.
Although numerous systems have been disclosed or suggested in the prior art for partial treatment of water, the systems suffer significant limitations. First, no prior art system of which the applicant is aware functions to remove all four specific contaminants which are found in waste wash water: (1) suspended solids; (2) organic contaminants; (3) bacteria; and (4) dissolved minerals. Further, none of the prior art systems of which applicant is aware operates as a complete recycling system, without water discharge.
Additionally, a significant deficiency the prior art relates to inaccuracies in describing systems which purportedly "purify" water or which are represented to yield the result of "pure" water. In reality, unless a system operates to remove all four contaminants (suspended solids, organic contaminants, bacteria and minerals) from water, the water cannot be said to be "purified." Also, the degree of removal of suspended solids is of particular interest. In vehicle washing operations, the majority of suspended solids are between 1 and 10 microns. Accordingly, a system which does not act to remove particles of the size present is not acting to "purify" the water. Yet, there is an increasing need for a system which can yield "pure" waters; and which can do so for relatively small volume applications, for example 500 to 4,000 gallons per day.
Accordingly, the present invention provides a new method and apparatus for purifying water by removing suspended solids, organic materials, bacteria and minerals from the water. Additionally, the present invention provides a system for purifying such water which is particularly suitable in water reclaiming and recycling operations, such as for vehicle washing facilities; and which is further practical in size, complexity and expense for operations treating under 5,000 gallons a day of water.